Orthopaedic prosthetic system for a rotating hinged-knee prosthesis

ABSTRACT

An orthopaedic prosthesis system includes a femoral component configured to be attached to a distal end of a patient&#39;s femur. A tibial tray is configured to be attached to a proximal end of a patient&#39;s tibia. A tibial insert is configured to be positioned between the femoral component and the tibial tray. An elongated pin rotatably couples the tibial insert to the femoral component.

This continuation application claims priority to U.S. patent applicationSer. No. 16/267,700, now U.S. Pat. No. 11,033,396, which was filed onFeb. 5, 2019 and is expressly incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to an orthopaedic prosthesissystem, including prosthetic components and methods for assembling theprosthetic components during an orthopaedic joint replacement procedure,and, more particularly, to orthopaedic prosthetic components and methodsfor assembling the prosthetic components during a knee replacementprocedure.

BACKGROUND

Movement (e.g., flexion and extension) of the natural human kneeinvolves movement of the femur and the tibia. Specifically, duringflexion and extension, the distal end of the femur and the proximal endof the tibia articulate relative to one another through a series ofcomplex movements. Damage (e.g., trauma) or disease can deteriorate thebones, articular cartilage, and ligaments of the knee, which canultimately affect the ability of the natural knee to function in such amanner. As a result, knee prostheses have been developed and implantedinto surgically-prepared ends of the femur and tibia.

A typical knee prosthesis for a total knee replacement, for example,includes a tibial component or tibial tray coupled to the patient'stibia, a femoral component coupled to the patient's femur, and a tibialinsert component positioned between the tibial tray and the femoralcomponent and including a surface to accommodate the condyles of thefemoral component. One type of knee prosthesis is a hinged kneeprosthesis, which typically includes a hinge mechanism to couple thefemoral component to one or both of the bearing component and the tibialcomponents in order to constrain and mechanically link the components ofthe knee prosthesis together.

SUMMARY

According to one aspect of the disclosure, an orthopaedic prosthesissystem includes a femoral component configured to be attached to adistal end of a patient's femur. A tibial tray is configured to beattached to a proximal end of a patient's tibia. A tibial insert isconfigured to be positioned between the femoral component and the tibialtray. The tibial insert includes an inferiorly-extending tab that isconfigured to engage the tibial tray to limit rotation of the tibialinsert relative to the tibial tray about a first axis extending in aninferior-superior direction. An elongated pin extends along a secondaxis extending in a medial-lateral direction. The elongated pinrotatably couples the tibial insert to the femoral component. Thefemoral component is configured to rotate about the second axis relativeto the tibial insert over a range of motion.

In some embodiments, the tibial tray may have a distal surfaceconfigured to engage a proximal end of a patient's tibia. A proximalsurface may be positioned opposite the distal surface. An outer wall mayextend between the distal surface and the proximal surface. Aposterior-facing channel may be defined by the outer wall. The tab ofthe tibial insert may be sized to be positioned in the posteriorchannel. The outer wall of the tibial tray may have a concave curvedsurface that defines a portion of the posterior-facing channel. The tabmay have a convex curved surface that is shaped to match the concavecurved surface such that engagement between the tab and the concavecurved surface prevents rotation of the tibial insert relative to thetibial tray about the first axis. The tibial insert may have a platformconfigured to engage the proximal surface of the tibial tray. The tabmay be removably coupled to the platform. The tab may be a first tab ofa plurality of tabs configured to be removably coupled the platform.Each tab of the plurality of tabs may have a size different from theother tabs to permit a different amount of rotation between the tibialinsert and the tibial tray.

In some embodiments, an elongated body extends from a first endconnected to the elongated pin and a second end positioned in a cavitydefined in the tibial insert. The elongated body may be configured tomove along the first axis in an inferior-superior direction between aninferior position and a superior position when the femoral component isrotated about the second axis relative to the tibial insert over therange of motion. The tibial insert may have an inner wall that definesthe cavity. The inner wall may have a tapered proximal surface thatdefines a proximal section of the cavity. The elongated body may have aproximal body section that is seated in the proximal cavity section whenthe modular insert is positioned in the inferior position. The innerwall of the tibial insert may have an inferior base surface. The taperedproximal surface of the tibial insert may extend from an elongatedopening defined in the platform to the inferior base surface.

In some embodiments, the elongated opening may have a substantially ovalshape. An opening may be defined in the inferior base surface. The innerwall of the tibial insert may have a distal surface that defines adistal section of the cavity. The elongated body may have a distal bodysection that extends into the distal cavity section. The elongated bodymay be permitted to rotate about the longitudinal axis relative to thetibial insert when the elongated body is positioned in the superiorposition.

According to another aspect of the disclosure, an orthopaedic prosthesissystem includes a first implantable prosthetic component that isconfigured to be attached to a distal end of a patient's femur. Thefirst implantable prosthetic component includes a first body having apair of spaced apart curved convex condyle surfaces. A second body isrotatably coupled to the first body. An elongated stem is coupled to thesecond body. A second implantable prosthetic component is configured tobe attached to a proximal end of a patient's tibia. An insert prostheticcomponent is configured to be positioned between the first implantableprosthetic component and the second implantable prosthetic component.The insert prosthetic component includes a cavity sized to receive theelongated stem of the first implantable prosthetic component. Aninferiorly-extending tab is configured to engage the second implantableprosthetic component to limit rotation of the insert prostheticcomponent relative to the second implantable prosthetic component abouta first axis extending in an inferior-superior direction. The first bodyis configured to rotate about a second axis relative to the insertprosthetic component over a first range of motion. The second axisextends in a medial-lateral direction.

In some embodiments, the second body may be configured to rotaterelative to the insert prosthetic component about a third axis extendingparallel to the second axis over a second range of motion. The secondrange of motion may be less than the first range of motion.

In some embodiments, the second implantable prosthetic component mayhave a distal surface configured to engage the proximal end of thepatient's tibia. A proximal surface may be positioned opposite thedistal surface. An outer wall may extend between the distal surface andthe proximal surface. A posterior-facing channel may be is defined bythe outer wall. The tab of the insert prosthetic component may be sizedto be positioned in the posterior channel. The outer wall of the secondimplantable prosthetic component may have a concave curved surface thatdefines a portion of the posterior-facing channel. The tab may have aconvex curved surface that is shaped to match the concave curved surfacesuch that engagement between the tab and the concave curved surfaceprevents rotation of the insert prosthetic component relative to thesecond implantable prosthetic component about the first axis. The insertprosthetic component may have a platform configured to engage theproximal surface of the second implantable prosthetic component. The tabmay be removably coupled to the platform. The tab may be a first tab ofa plurality of tabs configured to be removably coupled the platform.Each tab of the plurality of tabs may have a size different from theother tabs to permit a different amount of rotation between the insertprosthetic component and the second implantable prosthetic component.

According to yet another aspect of the disclosure, a method ofperforming an orthopaedic surgical procedure may include selecting atibial insert for use with a femoral component configured to be attachedto a distal end of a patient's femur and a tibial tray configured to beattached to a proximal end of a patient's tibia. The method may alsoinclude attaching a first tab to the tibial insert. The first tab isconfigured to permit a first range of rotation between the tibial trayand the tibial insert. The method may also include evaluating a range ofmotion of the patient's femur relative to the patient's tibia with thetibial insert and the first tab positioned between the distal end of thepatient's femur and the proximal end of the patient's tibia. The methodmay also include selecting a second tab configured to permit a secondrange of rotation between the tibial tray and the tibial insert. Themethod may also include attaching the second tab in place of the firsttab. The method may also include evaluating the range of motion of thepatient's femur relative to the patient's tibia with the tibial insertand the second tab positioned between the distal end of the patient'sfemur and the proximal end of the patient's tibia. The method may alsoinclude coupling the femoral component to the tibial insert with anelongated pin extending in a medial-lateral direction. The femoralcomponent is configured to rotate about a first axis defined by theelongated pin.

In some embodiments, the method may require inserting an elongated bodyinto a cavity defined in the tibial insert. The method may also requireinserting the elongated pin through the elongated body and the femoralcomponent to couple the femoral component to the tibial insert.

In some embodiments, evaluating the range of motion of the patient'sfemur relative to the patient's tibia with the tibial insert and thefirst tab positioned between the distal end of the patient's femur andthe proximal end of the patient's tibia may require rotating a proximalbody section of the elongated body about a second axis extendingparallel to the first axis to move the elongated pin between a firstposition and a second position. The second position may be locatedanterior of the first position.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is an exploded view of an orthopaedic knee prosthesis system;

FIG. 2 is a top perspective view of the tibial insert shown in FIG. 1and a posterior insert coupled to the tibial insert;

FIG. 3 is a bottom perspective view of the tibial insert shown in FIG. 2;

FIG. 4 is a top plan view of the tibial insert shown in FIG. 2 with theposterior insert removed;

FIG. 5 is a rear perspective view of the tibial insert shown in FIG. 4 ;

FIG. 6 is a rear perspective view of the posterior insert shown in FIG.2 ;

FIG. 7 is a bottom plan view of the tibial tray shown in FIG. 1 and thetibial insert shown in FIG. 1 coupled to the tibial tray;

FIG. 8 is an exploded view of the modular insert shown in FIG. 1 ;

FIG. 9 is a bottom perspective view of the body of the modular insertshown in FIG. 1 ;

FIG. 10 is a side perspective view of the modular insert shown in FIG. 1;

FIG. 11 is a side perspective view of the orthopaedic knee prosthesissystem shown in FIG. 1 ;

FIG. 12 is a cross-sectional view of the orthopaedic knee prosthesissystem in an extended position taken along line 12-12 shown in FIG. 11 ;

FIG. 13 is a view similar to FIG. 12 showing the orthopaedic kneeprosthesis system in a flexed position;

FIG. 14 is a cross-sectional view of the orthopaedic knee prosthesissystem in an extended position taken along line 14-14 shown in FIG. 12 ;

FIG. 15 is a cross-sectional view of the orthopaedic knee prosthesissystem in a flexed position taken along line 15-15 shown in FIG. 13 ;

FIG. 16 is a top plan view of the modular insert and tibial insert shownin FIG. 1 with the modular insert in a rotated position; and

FIG. 17 is a top plan view of the tibial insert and the tibial trayshown in FIG. 1 with the tibial insert in a rotated position.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants andorthopaedic surgical instruments described herein as well as inreference to the patient's natural anatomy. Such terms havewell-understood meanings in both the study of anatomy and the field oforthopaedics. Use of such anatomical reference terms in the writtendescription and claims is intended to be consistent with theirwell-understood meanings unless noted otherwise.

Referring now to FIG. 1 , an orthopaedic knee prosthesis system 10 isshown. The orthopaedic knee prosthesis system 10 includes a femoralcomponent 12 configured to be coupled to a distal end of a patient'sfemur, a tibial tray 16 that is configured to be coupled to a proximalend of a patient's femur, and a tibial insert 18 configured to beassembled separately with the tibial tray 16. The femoral component 12,the tibial tray 16, the tibial insert 18, and a modular insert 22 may beseparately assembled to form an orthopaedic knee prosthesis;specifically, a hinged orthopaedic knee prosthesis, as described below.

The system 10 is configured to articulate through three ranges ofmotion. The system 10 moves through various degrees of flexion betweenfull extension and full flexion. As the system 10 articulates through arange of flexion a contact point between condyles of the femoralcomponent 12 and condyle surfaces of the tibial insert 18 moves so thatthe contact point is different at different degrees of flexion.Additionally, the surgeon can selectively add rotation about asuperior-inferior axis. The rotation may occur between the femoralcomponent 12 and the tibial insert 18. The rotation may also occurbetween the tibial insert 18 and the tibial tray 16. As the system movesto within a first range of flexion, the contact point between thecondyles and the condyle surfaces moves in an anterior-posteriordirection. During a second range of flexion that is within the firstrange of flexion, the femoral component 12 may be permitted to rotaterelative to the tibial insert 18. In some embodiments, the surgeon mayalso selectively permit the tibial insert 18 to rotate relative to thetibial tray 16 throughout the first range of flexion. An amount ofrotation of the tibial insert 18 relative to the tibial tray 16 may beadjusted by the surgeon.

In the illustrative embodiment, the femoral component 12 includes a post24 that is configured to be implanted into the distal end of thepatient's femur. The post 24 is attached to a body 26 having a pair ofspaced-apart lateral and medial condyles 28. The condyles 28 includerespective lateral and medial condyle surfaces 30, 32, which are curvedconvexly. An intercondylar notch 34 is defined between the lateral andmedial condyles 28 and is sized to receive the modular insert 22. Thefemoral component 12 also includes a posterior bore 40 that extends in amedial-lateral direction through the lateral and medial condyles 28. Asdescribed in greater detail below, the bore 40 forms part of the hingemechanism and is sized to receive a hinge pin 42.

The femoral component 12 and the tibial tray 16 are each formed from animplant grade metallic material such as, for example, cobalt chromium.As shown in FIG. 1 , the tibial tray 16 includes a base 50 and an anchor52 that extends inferiorly from a distal surface 54 of the base 50. Thebase 50 is sized and shaped to conform to the configuration of asurgically-prepared proximal surface of the patient's tibia, and theanchor 52 is sized and shaped to be implanted into a surgically-preparedintramedullary canal of the patient's tibia.

The base 50 includes a substantially planar proximal surface 60 that ispositioned opposite the distal surface 54. A curved outer wall 62extends between from the surfaces 54, 60 and is sized and shaped toconform to the outer edge of the surgically-prepared proximal surface ofthe patient's tibia. A concave posterior-facing channel 66 is formed bythe outer wall 62. An opening 64 is defined in the proximal surface 60,and the tray 16 includes an aperture 70 that extends inwardly from theopening 64. The aperture 70 extends through the base 50 and into theanchor 52.

The tibial tray 16 may be assembled with the tibial insert 18 shown inFIG. 1 to form a tibial component. The insert is formed from an implantgrade plastic material such as, for example, ultra-high molecular weightpolyethylene (UHMWPE). The tibial insert 18 includes a platform 72 thatis sized to be positioned on the proximal surface 60 of the tibial tray16 and an elongated stem 74 that extends inferiorly from a distalsurface 76 of the platform 72 along a longitudinal axis 78 that extendsin an inferior-superior direction. Similar to the proximal surface 60 ofthe tibial tray 16, the distal surface 76 of the platform issubstantially planar. The platform 72 also includes a pair of concavecurved proximal surfaces 80, 82 that correspond to the lateral andmedial condyle surfaces 30, 32 of the femoral component 12. The platform72 also includes a curved outer wall 84 that extends between thesurfaces 80, 82.

Referring now to FIG. 2 , an opening 90 is defined in the proximalsurfaces 80, 82 of the platform 72. The tibial insert 18 includes anaperture 92 that extends inwardly from the opening 90 through theplatform 72 and into the elongated stem 74. The aperture 92 then extendsalong the longitudinal axis 78 of the stem 74.

When coupled to the tibial tray 16, the distal surface 76 of the tibialinsert 18 engages the proximal surface 60 of the tibial tray. Theelongated stem 74 of the tibial insert 18 is sized to be received in theaperture 70 of the tibial tray 16 when the tibial insert 18 is coupledto the tibial tray.

Referring back to FIG. 1 , the modular insert 22 includes an elongatedstem 100 (shown in FIG. 8 ) that extends along the longitudinal axis 78.A proximal body 104 is pivotally attached to the stem 100. The stem 100is sized and shaped to be inserted in the opening 90, and extend intothe aperture 92, of the tibial insert 18. The proximal body 104 includesa medial opening 106, a lateral opening 108, and an inner wall 110extending between the medial opening 106 and the lateral opening 108.The inner wall 110 defines a cylindrical pin hole 112 that extendsthrough the proximal body 104.

The proximal body 104 of the modular insert is sized and shaped to bepositioned within the intercondylar notch 34 of the femoral component 12such that the posterior bore 40 may be aligned with the passageway 116of the modular insert 22. The hinge pin 42 extends through the posteriorbore 40 and the passageway 116 along a longitudinal axis 20 that extendsin a medial-lateral direction to attach the modular insert 22 to thefemoral component 12. As described above, the tibial tray 16 and thetibial insert 18 may be combined with the femoral component 12 and themodular insert 22 to form a hinged orthopaedic knee prosthesis.

Referring to FIGS. 2 and 3 , a posterior component 130 is removablycoupled to a posterior side 132 of the platform 72 of the tibial insertwith fasteners 136. The posterior component 130 limits an amount ofrotation between the tibial insert 18 and the tibial tray 16. In someembodiments, a plurality of posterior components 130 may be provided,wherein each posterior component 130 provides a different predeterminedamount of rotation between the tibial insert 18 and the tibial tray 16.In some embodiments, a posterior component 130 may be provided tocompletely prevent rotation between the tibial insert 18 and the tibialtray 16. The posterior component 130 includes an inferiorly-extendingtab 134 extending from a surface of the posterior component 130. The tab134 extends from the distal surface 76 of the tibial insert 18 when theposterior component 130 is coupled to the tibial insert 18. In someembodiments, the posterior component 130 is formed integrally with thetibial insert 18. The tab 134 extends a length 138 from the distalsurface 76. The tab 134 includes a planar side wall 140 extending alongthe posterior side 132 of the tibial insert 18. A curved convex sidewall 142 extends in an anterior direction from the planar side wall 140.The curved side wall 142 extends below the distal surface 76 of thetibial insert 18.

The curved side wall 142 is sized to be positioned within the channel 66of the tibial tray 16. The curved side wall 142 is sized smaller thanthe channel 66 so that the tibial insert 18 is permitted to rotaterelative to the tibial tray 16, as described in more detail below. Inother embodiments, the tab 134 of the different posterior component 130includes a curved side wall 144 (shown in broken lines) that is sized tobe secured within the channel 66 to prevent rotation of the tibialinsert 18 relative to the tibial tray 16, as described in greater detailbelow. As noted above, the system 10 may include multiple posteriorcomponents 130 having different sized tabs 134. Accordingly, the surgeoncan select a tab size based on a preferred amount of rotation. In someembodiments, the tibial tray 16 rotates in increments of 5 degrees from0 to +/−20 degrees.

As illustrated in FIGS. 4 and 5 , the tibial insert 18 includes amounting cavity 168 that extends from a superior opening 170 formed inthe proximal surfaces 80, 82 and an opening 172 formed in the posteriorside 132. The mounting cavity 168 is sized to receive the posteriorcomponent 130, when the posterior component 130 is coupled to the tibialinsert 18. A cavity 174 extends from the openings 170 and 172 and issized to receive the posterior component 130. The cavity 174 includes apair of posterior planar side walls 176 extending from the superioropening 170 to a bottom wall 178. A curved end wall 180 extends from thebottom wall 178 to the distal surface 76 of the tibial insert 18. A pairof openings 182 is formed in the curved end wall 180. A bore 184 extendsfrom each opening 182 into the tibial insert 18. Curved notches 186extend medially and laterally from the curved end wall 180 along theposterior side 132 of the tibial insert 18.

Referring now to FIG. 6 , the posterior component 130 includes a body196. The tab 134 extends inferiorly from the body 196. A pair of upperflanges 198 extends in an anterior direction from the body 196. Theupper flanges 198 are sized and shaped to be received in the proximalcavity 154 of the tibial insert 18. A pair of lower flanges 200 extendsmedially and laterally from the body 196. Each of the pair of lowerflanges 200 is sized and shaped to position in a respective curved notch186 of the tibial insert 18.

A pair of openings 202 is formed in a posterior end 204 of the body 196.A bore 188 extends inward from each of the pair of openings 202 throughthe body 196 of the posterior component 130. The bores 188 areconfigured to align with the bores 174 of the tibial insert 18 when theposterior component 130 is coupled to the tibial insert 18. Thefasteners 136 are received in the bores 174 and the bores 188 to securethe posterior component 130 to the tibial insert 18. In someembodiments, the bores 138 and 174 are threaded to receive a threadedfastener 136.

FIG. 7 illustrates the tab 134 of the posterior component 130 extendinginto the channel 66 of the tibial tray 16 when the tibial insert 18 iscoupled to the tibial tray 16. The channel 66 of the tibial tray 16includes a curved side wall 206 extending from an opening 208 having alength 210. The tab 134 is sized so that the planar side wall 140 has alength less than the length 210 of the opening 208. Also, the curvedside wall 142 of the tab 134 is sized to be smaller than the curved sidewall 206 of the channel 66 to permit movement of the tab 134 within thechannel 66. A combination of the size of the planar side wall 140 andthe size of the curved side wall 142 relative to the size of the channel66 permits limited rotation of the tibial insert 18 relative to thetibial tray 16. That is, the tibial insert 18 is permitted to rotateabout the longitudinal axis 78 until the curved side wall 142 of the tab134 contacts the curved side wall 206 of the channel 66.

In another embodiment, the tab 134 includes curved side wall 144. Insuch an embodiment, the planar side wall 140 has a length 212 that issubstantially equal to the length 210 of the opening 208. Additionally,the curved side wall 144 of the tab 134 is sized to contact the curvedside wall 206 of the channel 66 to prevent rotation of the tibial insert18 relative to the tibial tray 16.

Referring back to FIG. 4 , the aperture 92 of the tibial insert 18includes a tapered inner wall 150 extending from the platform 72 to aninferior base wall 152 to define a proximal cavity 154 extendinglongitudinally through the platform 72. The inner wall 150 is slopedradially inward from the platform 72 to the inferior base wall 152. Theinner wall 150 is substantially oval in shape so that the proximalcavity 154 includes a major axis 156 extending in the anterior-posteriordirection and a minor axis 158 extending in the medial-lateraldirection. The major axis 156 has a length 160 that is greater than alength 162 of the minor axis 158. In some embodiments, the minor axis158 extends in the anterior-posterior direction, and the major axis 156extends in the medial-lateral direction. At the platform 72, the majoraxis 156 and the minor axis 158 each have a maximum length. Due to theslope of the inner wall 150, the major axis 156 and the minor axis 158have a minimum length at the inferior base wall 152. The lengths of themajor axis 156 and the minor axis 158 gradually decrease through variousintermediate lengths between the platform 72 and the inferior base wall152.

An opening 164 is formed in the inferior base wall 152. A distal cavity166 extends from the opening 164. The distal cavity 166 is generallycylindrical in shape and extends from the opening 164 to a bottom wall168. The distal cavity 166 is sized to receive the elongated stem 100 ofthe modular insert 22.

Referring now to FIG. 8 , the elongated stem 100 of the modular insert22 extends between a distal end 220 and a proximal end 222. The distalend 220 of the elongated stem 100 is sized to position in the distalcavity 166 of the tibial insert 18. The proximal end 222 includes arounded outer wall 226 and a pair of linear side walls 228 extendingfrom the rounded outer wall 226. A pin hole 230 extends between a pairof openings 232 formed in the proximal end 222. Each of a pair ofbushings 240 is sized to be positioned bin one of the openings 232.

Each bushing 240 includes a body 242 and a flange 244 extending aroundthe body 242. The flange 244 has a diameter 246 that is greater than adiameter 248 of the body 242. The diameter 248 of the body 242 is sizedso that the body 242 positions within the opening 232. The diameter 246of the flange 244 is sized so that the flange 244 positions against therespective side wall 228.

Each bushing 240 includes a pin hole 250 extending between a pair ofopenings 252. The pin hole 250 is sized to receive a pin 254 along alongitudinal axis 256 that extends parallel to the longitudinal axis 20in a medial-lateral direction. The pin 254 includes a cylindrical shaft258 having a diameter 260 sized to a diameter 270 of the pin hole 250. Athreaded head 272 extends from the shaft 258. The threaded head 272 hasa diameter 274 that is greater than the diameter 260 of the shaft 258.

The proximal body 104 of the modular insert 22 includes a distal section280 and a spine 282 extending proximally from the distal section 280. Afastener 284 is configured to secure the spine 282 to the distal section280. The distal section 280 is sized to position in the proximal cavity154 of the tibial insert 18. The distal section 280 includes an outerside wall 286 that is sized and shaped to the inner wall 150 of thetibial insert 18. The outer side wall 286 is generally oval in shape andslopes from superior end 288 to an inferior end 298. The distal section280 is configured to receive the proximal end 222 of the elongated stem100.

Referring now to FIG. 9 , the outer side wall 286 includes a major axis290 extending in the anterior-posterior direction and a minor axis 292extending in the medial-lateral direction. The major axis 290 has alength 294 that is greater than a length 296 of the minor axis 292. Insome embodiments, the major axis 290 extends in the medial-lateraldirection and the minor axis 292 extends in the anterior-posteriordirection. The distal section 280 includes a cavity 300 extending froman opening 302 in a distal end 304 of the distal section 280. The cavity300 is sized and shaped to receive the proximal end 222 of the elongatedstem 100.

At the superior end 288, the major axis 290 and the minor axis 292 eachhave a maximum length. Due to the slope of the outer side wall 286, themajor axis 290 and the minor axis 292 have a minimum length at theinferior end 298. The lengths of the major axis 290 and the minor axis292 gradually decrease through various intermediate lengths between thesuperior end 288 and the inferior end 298.

The outer side wall 286 is configured to engage the inner wall 150 ofthe tibial insert 18, when the modular insert 22 is coupled to thetibial insert 18. At an initial extended position, the distal section280 of the modular insert 22 is seated in the aperture 92 of the tibialinsert 18 with the inferior end 298 positioned against the inferior basewall 152 of the tibial insert 18. The outer side wall 286 is positionedagainst the inner wall 150 of the tibial insert 18. During flexion ofthe femoral component 12 relative to the tibial insert 18, the modularcomponent 22 moves in a superior direction so that the inferior end 298is separated from the inferior base wall 152 of the tibial insert 18. Ina separated position, the axes 290, 292 of the modular insert 22 arepositioned so that a length of the axes 290, 292 at any given locationis less than a length of an aligned axis 156, 158. For example, the axis156, 158 at the platform 72 are aligned with an intermediate axis 290,292 of the modular insert 22 that has a shorter length, therebypermitting rotation of the modular insert 22 relative to the tibialinsert 18.

Referring back to FIG. 8 , a threaded bore 310 extends from openings 312in the distal section 280 and into the cavity 300. As illustrated inFIG. 10 , when the proximal end 222 of the elongated stem 100 isreceived in the cavity 300, the threaded bore 310 is configured to alignwith the pin hole 230 of the elongated stem 100 and the pin holes 250 ofthe bushings 240 to define a passageway 320. The passageway 320 isconfigured to receive the pin 254 to hingedly attach the distal section280 to the elongated stem 100. The threaded head 272 is secured tothreads 322 of the bore 310 to secure the pin 254 to the distal section280. The proximal body 104 of the modular insert 22 is configured torotate about the longitudinal axis 256 in the direction of arrow 324relative to the elongated stem 100.

The spine 282 of the proximal body 104 includes the passageway 116extending between the medial opening 106 and the lateral opening 108.Each opening 106, 108 is sized and shaped to receive a bushing 334. Eachbushing 334 includes a bore 336 extending between openings 338. Asillustrated in FIG. 11 , the bores 336 are configured to align with theposterior bore 40 of the femoral component 12, when the femoralcomponent 12 is coupled to the modular insert 22. The hinge pin 42extends through the posterior bore 40, the passageway 116, and the bores336 to pivotally attach the modular insert 22 to the femoral component12 along a longitudinal axis 20. The femoral component 12 is configuredto rotate about arrow 340, when the femoral component 12 is coupled tothe modular insert 22.

During an operation to replace a patient's knee, the surgeon selects afemoral component 12 and a tibial tray 16. An end of the patient's femurand an end of the patient's tibia are resected to prepare for insertionof the system 10. The surgeon drills intramedullary canals in the femurand the tibia to receive the post 24 of the femoral component 12 and thestem 74 of the tibial tray 16, respectively. Generally, the system 10includes various femoral components 12 and tibial trays 16 of differentsizes. The surgeon selects the femoral component 12 and tibial tray 16based on an anatomy of the patient's knee. The femoral component 12 iscoupled to the end of the femur by inserting the post 24 into theintramedullary canal of the femur. Likewise, the tibial tray 16 iscoupled to the tibia by inserting the stem 74 into the intramedullarycanal of the tibia.

The surgeon then selects a tibial insert 18 from a plurality of tibialinserts 18 having different sizes. Each tibial insert 18 may havedifferent sized and shaped condyle surfaces 30, 32. The surgeon tests arange of motion of the system 10 by moving the femoral component 12through a first range of motion between a fully extended position and afully flexed position. During flexion of the system 10, the surgeonevaluates the movement of the femoral component 12 along the tibialinsert 18. The surgeon may elect to test multiple tibial inserts 18until a desired range of motion is achieved.

As described below, the tibial insert 18 may also be selected based on asize of the proximal cavity 154 of the tibial insert 18. The size of theproximal cavity 154 varies to provide rotation between the modularinsert 22 and the tibial insert 18.

A posterior component 170 is selected to couple to the tibial insert 18from a plurality of posterior components 170. Each of the posteriorcomponents 170 includes a tab 134 having different sized planar sidewalls 140 and curved side walls 142. In some embodiments, the posteriorcomponent 170 is formed integrally with the tibial insert 18, and eachtibial insert 18 has a different sized tab 134. With the posteriorcomponent 170 coupled to the tibial insert 18, the surgeon test a rangeof rotation of the tibial insert 18 relative to the tibial tray 16. Thesurgeon selects the posterior component 170 based on a desired range ofrotation. In some embodiments, the surgeon may elect to select aposterior component 170 that prevents rotation of the tibial insert 18relative to the tibial tray 16.

A modular insert 22 is selected from a plurality of modular inserts 22having different sizes. The size of the modular insert 22 is selected sothat the distal section 280 of the modular insert 22 sits in theproximal cavity 154 in a seated position when the system is fullyextended. The surgeon again tests the system 10 by flexing the femoralcomponent 12 through the first range of motion. At an intermediateflexion, the femoral component 12 enters a second range of flexion thatis within the first range of flexion. The second range of flexion isbetween the intermediate flexion and the full extension. At theintermediate flexion, the distal section 280 of the modular insert 22becomes unseated within the proximal cavity 154.

Through the second range of flexion, the distal section 280 is pulledupward within the proximal cavity 154 so that the modular insert 22 isallowed to rotate relative to the tibial insert 18. The surgeon teststhe range of rotation of the modular insert 22 and selects a modularinsert 22 that provides a desired range of flexion. In some embodiments,the surgeon may elect to use a different tibial insert 18 with adifferent sized proximal cavity 154 to achieve the desired range ofrotation. The surgeon may also select the modular insert 22 and tibialinsert 18 based on a range of motion the second range of flexion.

Accordingly, during the procedure the surgeon tests multiple ranges ofmotion to select the desired components. The surgeon evaluates the firstrange of motion from full extension to full flexion, as well as, thesecond range of motion from the intermediate flexion to full flexion.Further, the surgeon evaluates a first range of rotation of the tibialinsert 18 relative to the tibial tray 16, and a second range of rotationof the modular insert 22 relative to the tibial insert 18. It should benoted that the second range of rotation may be within the first range ofrotation.

Referring now to FIG. 12 , in a fully extended position 400, theelongated stem 100 extends into the distal cavity 166 of the tibialinsert 18 to an inferior position 398 such that a tip 402 of the distalend 220 is positioned adjacent a bottom 404 of the distal cavity 166.The elongated stem 100 extends along the longitudinal axis 78. Thedistal section 280 of the proximal body 104 of the modular insert 22 isseated in the cavity 300. The hinge pin 42 is located in a fullyextended position 416. As illustrated in FIG. 14 , the outer side wall286 of the distal section 280 is positioned against the inner wall 150of the tibial insert 18. The outer side wall 286 of the distal section280 is in contact with the inner wall 150 of the tibial insert 18 toprevent medial-lateral rotation of the modular insert 22 relative to thetibial insert 18 and to maintain the modular insert 22 in a fixedposition 412.

Referring to FIG. 13 , in a fully flexed position 420, the femoralcomponent 12 is rotated about the longitudinal axis 20, as indicated byarrow 422, over the first range of flexion, which includes the secondrange of flexion. In some embodiments, the first range of flexion iswithin −3 to 140 degrees. Engagement of curved convex condyle surfaces30, 32 and the curved proximal surfaces 58, 60 during the first range offlexion causes the modular insert 22 to move upward in the proximalcavity 154 from the inferior position 398 to a superior position 396. Asthe femoral component 12 rotates, the elongated stem 100 moves in asuperior direction, as indicated by arrow 424, within the distal cavity166 to the superior position 396 so that the tip 402 of the distal end220 advances away from the bottom 404 of the distal cavity 166. Theproximal body 104 of the modular insert 22 also advances in the superiordirection, so that the distal section 280 is raised in the cavity 300.

The proximal body 104 of the modular insert 22 then rotates about thelongitudinal axis 256 relative to the elongated stem 100, as indicatedby arrow 430, over the second range of motion from the intermediateflexion to full extension. In some embodiments, the second range offlexion is within 3 to 10 degrees. The second range of motion overlapsthe first range of motion. During the second range of flexion of thefemoral component 12, the longitudinal axis 20 moves relative to thelongitudinal axis 256 over the second range of motion. As thelongitudinal axis 20 moves relative to the longitudinal axis 256 thehinge pin 42 moves between the fully flexed position 416 and a fullyextended position 418. The second position 418 is located anterior ofthe first position 416.

As illustrated in FIG. 15 , during the second range of flexion, theouter side wall 286 of the distal section 280 is separated from theinner wall 150 of the tibial insert 18, thereby enabling medial-lateralrotation of the modular insert 22 relative to the tibial insert 18. Themodular insert 22 rotates about the longitudinal axis 78 to a rotatedposition 432, an example of which is provided in FIG. 16 .

When the femoral component 12 is returned to the extended position 400,the modular insert 22 advances distally into the distal cavity 166 sothat the outer side wall 286 of the distal section 280 engages the innerwall 150 of the tibial insert 18, thereby rotating the modular insert 22back to the fixed position 412.

Referring now to FIG. 17 , the tibial insert 18 is also capable ofrotating medially-laterally relative to the tibial tray 16 in someembodiments. In embodiments where the curved side wall 142 of the tab134 is sized smaller than the curved side wall 206 of the channel 66,the tibial insert 18 rotates about the longitudinal axis 78 in eitherthe extended position 400 or the flexed position 420. The tibial insert18 is permitted to rotate either medially or laterally to a rotatedposition 440, an example of which is provided in FIG. 17 . A range ofrotation is determined by a size of the tab 134. A smaller tab 134 willprovide more rotation than a larger tab 134. The tibial insert 18 ispermitted to rotate until the curved side wall 142 of the tab 134contacts the curved side wall 206 of the channel 66.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the devices and assemblies describedherein. It will be noted that alternative embodiments of the devices andassemblies of the present disclosure may not include all of the featuresdescribed yet still benefit from at least some of the advantages of suchfeatures. Those of ordinary skill in the art may readily devise theirown implementations of the devices and assemblies that incorporate oneor more of the features of the present invention and fall within thespirit and scope of the present disclosure as defined by the appendedclaims.

The invention claimed is:
 1. A hinged orthopaedic knee prosthesis system, comprising: a femoral component configured to be attached to a distal end of a patient's femur; a tibial tray configured to be attached to a proximal end of a patient's tibia, the tibial tray including a curved outer wall; a tibial insert configured to be positioned between the femoral component and the tibial tray, the tibial insert including a platform, an elongated stem that extends inferiorly from a distal surface of the platform, and a posterior component removably coupled to a posterior side of the platform, wherein the posterior component includes an inferiorly-extending tab that is configured to engage the curved outer wall of the tibial tray to limit rotation of the tibial insert relative to the tibial tray about a first axis extending in an inferior-superior direction, wherein the femoral component is coupled to the tibial insert and configured to rotate, relative to the tibial insert and over a range of motion, about a second axis substantially orthogonal to the first axis.
 2. The hinged orthopaedic knee prosthesis system of claim 1, wherein the posterior component is coupled to the platform of the tibial inset via at least one fastener.
 3. The hinged orthopaedic knee prosthesis system of claim 2, wherein the posterior component comprises a body having a pair of bores defined in a posterior side of the body and extending through the body, wherein the platform includes a pair of threaded bores defined on a posterior side of the platform and wherein each bore of the posterior component aligns with a corresponding threaded bore of the platform when the posterior component is coupled to the platform, and wherein a fastener is received in each corresponding pair of bore and threaded bore secure the posterior component to the platform.
 4. The hinged orthopaedic knee prosthesis system of claim 1, wherein the tibial tray includes a channel defined in a posterior side of the curved outer wall, and wherein the inferiorly-extending tab of the posterior component is received in the channel of the tibial tray when tibial insert is coupled to the tibial tray to limit rotation of the tibial insert relative to the tibial tray about the first axis.
 5. The hinged orthopaedic knee prosthesis system of claim 4, wherein the inferiorly-extending tab is sized to allow an amount of rotation of the tibial insert relative to the tibial tray and wherein the inferiorly-extending tab moves within the channel of the tibial tray during rotation of the tibial insert relative to the tibial tray.
 6. The hinged orthopaedic knee prosthesis system of claim 4, wherein the inferiorly-extending tab is sized to prevent rotation of the tibial insert relative to the tibial tray.
 7. The hinged orthopaedic knee prosthesis system of claim 4, wherein the inferiorly-extending tab includes a planar posterior side wall and a curved convex side wall that extends in an anterior direction from the planar posterior side wall.
 8. The hinged orthopaedic knee prosthesis system of claim 7, wherein the planar posterior side wall of the inferiorly-extending tab has a length that is less than a width of a posterior opening of the channel.
 9. The hinged orthopaedic knee prosthesis system of claim 7, wherein the planar posterior side wall of the inferiorly-extending tab has a length that is substantially equal to a width of a posterior opening of the channel.
 10. The hinged orthopaedic knee prosthesis system of claim 1, wherein the inferiorly-extending tab that is configured to engage the curved outer wall of the tibial tray to limit rotation of the tibial insert relative to the tibial tray to a degree of rotation in a range of 5 to 20 degrees.
 11. The hinged orthopaedic knee prosthesis system of claim 1, wherein the posterior component comprises a first posterior component, and wherein the hinged orthopaedic knee prosthesis system further comprises a plurality of posterior components configured to be separately coupled to the platform, the plurality of posterior components including the first posterior component, wherein each posterior component includes a corresponding inferiorly-extending tab configured to engage the curved outer wall of the tibial tray to limit rotation of the tibial insert relative to the tibial tray by a different amount of degrees of rotation relative to each other posterior component.
 12. The hinged orthopaedic knee prosthesis system of claim 11, wherein the plurality of posterior components further includes a second posterior component, a third posterior component, and a fourth posterior component, wherein the first posterior component limits the rotation of the tibial insert relative to the tibial tray to about 5 degrees of rotation, the second posterior component limits the rotation of the tibial insert relative to the tibial tray to about 10 degrees of rotation, the third posterior component limits the rotation of the tibial insert relative to the tibial tray to about 15 degrees of rotation, and the fourth posterior component limits the rotation of the tibial insert relative to the tibial tray to about 20 degrees of rotation.
 13. The hinged orthopaedic knee prosthesis system of claim 1, wherein the posterior component includes a body, a pair of upper flanges extending in an anterior direction from the body, a first lower flange extending medially from the body, and a second lower flange extending laterally from the body, wherein the pair of upper flanges are configured to be received in a corresponding proximal cavity of the platform and each lower flange is configured to be received in a corresponding notch of the platform when the posterior component is coupled to the platform.
 14. The hinged orthopaedic knee prosthesis system of claim 1, wherein the inferiorly-extending tab extends below a distal surface of the platform of the tibial insert and below a proximal surface of the tibial tray when the tibial insert is coupled to the tibial tray.
 15. The hinged orthopaedic knee prosthesis system of claim 1, further comprising a modular insert having a proximal body and an elongated stem extending inferiorly from the proximal body, wherein the elongated stem is configured to be received in a cavity defined in the tibial insert between a pair of curved proximal surfaces of the tibial insert.
 16. The hinged orthopaedic knee prosthesis system of claim 15, further comprising an elongated pin extending along a second axis extending in a medial-lateral direction, the elongated pin rotatably coupling the modular insert to the femoral component, wherein the femoral component is configured to rotate about the second axis relative to the tibial insert over a range of motion.
 17. The hinged orthopaedic knee prosthesis system of claim 15, wherein the tibial insert includes an inner wall that defines the cavity, the inner wall including a tapered proximal surface that defines a proximal section of the cavity, and the proximal body of the modular insert is seated in the proximal cavity section when the modular insert is coupled to the tibial insert.
 18. The hinged orthopaedic knee prosthesis system of claim 17, wherein the inner wall of the tibial insert includes an inferior base surface, and the tapered proximal surface of the tibial insert extends from an elongated opening defined in the platform to the inferior base surface.
 19. The hinged orthopaedic knee prosthesis system of claim 18, wherein the elongated opening has a substantially oval shape.
 20. The hinged orthopaedic knee prosthesis system of claim 18, wherein: an opening is defined in the inferior base surface, the inner wall of the tibial insert includes a distal surface that defines a distal section of the cavity, and the elongated stem includes a distal body section that extends into the distal cavity section. 